Ultrahigh strength triggered by BCC and B2 eutectic-phase interfaces in a novel FeCrVNiAl high-entropy alloy

The strength−ductility tradeoff and composition homogeneity have been the obstacles to obtaining advanced structural alloys. To overcome the limitations, we develop a novel coherently eutectic high-entropy alloy, i.e. Fe₃₀Cr₁₅V₁₅Ni₂₀Al₂₀. By introducing a BCC phase with a low lattice misfit (0.13%) and constructing the BCC/B2 eutectic-phase interfaces, the alloy shows high mechanical stability. The low lattice mismatch contributes to the good stability of the phase interfaces and inhibits crack initiation. Thus, the as-cast Fe₃₀Cr₁₅V₁₅Ni₂₀Al₂₀ alloy shows an excellent tensile yield strength of 929 MPa and a high yield compressive strength of 2423 MPa. In addition, it shows an excellent compressive strain of 22.3%.